Party-line system of telephones.



N0. 827,825. PATENTED AUG. 7, 1906.

H. B. STOCKS.

PARTY LINE SYSTEM OF TELBPHONES. Ar'rLIoATIoN FILED SEPT.5,1905.

5 SHEETS-SHEET 1.

No. 827,825. PATEN-TED AUG; 7, 1906- H. B. STOCKS.

PARTY LINE SYSTEM OF TELEPHONES.

APPLIOATION FILED SEPT. 5.1905.

' c. ms NORRIS PETERS 00., \vnsmuarmv, n

No. 827,825. PATBNTED AUG. 7, 1906. H. B. STOCKS.

PARTY LINE SYSTEM OF TELBPHONES. APPLIOATION nun saw. a. 1905.

5 sums-sans! a.

Tu: "cams PETERS ca, WASHINGTON. oc.

N0. 827,825. PATENTED AUG. 7, 1906' H. B. STOCKS.

PARTY LINE SYSTEM OF TBLEPHONES.

APPLICATION FILED ssr'r. 5.1905.

5 SHEETS-SHEET 4.

rue: NORRIS Psrsres co,, WASHINGTON, n c.

Nb. 827,825. .PATENTED AUG. 7, 1906.

H. B. STOCKS. PARTY LINE SYSTEM OF TBLEPHONES. APPL IIIIIIIIIII D SEPT. 5. 1905.

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"III

lllllll II UN TE STATES PATENT OFFICE.

PARTY- -LINE SYSTEM OF TELEPHONES.

Specification of Letters Patent.

Patented Aug. 7, 1906.

Application filed September 5, 1905. Serial No. 276.998-

To all whom it may concern:

Be it known that I, HARRY BENWELL STOCKS, engineer, a subject of the King of Great Britain, residing at .Stanton, 124 Barlow Moor road, Ohorlton-cum-Hardy, Manchester, in the county of Lancaster, England, have invented new and useful Improvements in or Relating to the Party-Line System of Telephones, of which the following is a specification.

My invention has for its object the provision of switching apparatus at subscribers instruments (orother suitable position on the line-wires of a party-line system) which shall be capable of operation by the person in charge of the line at the switchboard in the exchange, and at the same time said switching apparatus shall not be under the control,

directly or indirectly, of the subscriber unless it is desired that it be so arranged, and at the completion of a call provision is made whereby all switches return to zero position, so that perfect synchronism of the movements of all switch apparatus is assured.

In the accompanying drawings, Figure 1 represents an end elevation of a subscribers switch apparatus. Fig. 2 is a plan view of same. Fig. 3 is a side elevation looking in the direction of the arrow, Fig. 2. Fig. 4 is aside elevation of the switch from the opposite side. Fig. 5 is a diagram of the circuits. Fig.- 6 is a separate view of the switch-drum. Fig. 7 is a sectional elevation thereof. Fig. 8 is a view in flat projection of the five switchdrums, showing all the contacts on such drums, it being assumed that five subscribers are on the party-line. Fig. 9 is an elevation of the operators switch. Fig. 10 is a plan thereof and shows the connections to the party-line X and X In carrying my invention into effect I provide that each switch apparatus, hereinafter called the switch, and which is'illustrated in Figs. 1 to 4, shall consist of an electromagnet a or other apparatus capable of working by the passage of an electric current, which electromagnet by means of a pawl 1), connected to an armature c, intermittently rotates a ratchet-wheel d, secured to the spindle e of a drum f, a tooth at a time at each vibration of the armature. A looking-detent 2 serves to lock the ratchet-wheel. The drum f thus intermittently rotated carries the necessary contacts whereby one or more subscribers may be arranged in talking-circuit.

In Fig. 8 is shown in flat projection the drums and contacts thereon for five subscribers of a party-line. This drum is so designed that with reference to the other parts of the mechanism, as hereinafter described, only two brushes are necessary to complete the circuits of the telephone required that talking may be carried on over the line.

The construction of the drum is shown particularly in Figs. 6 and 7. On a central steel spindle e is mounted a bush h, of vulcanite or other insulating material. On this is placed a sleeve 6, of brass, having an enlarged end 7c with'an extension Z, which extension forms the zero position for all the switch-drums, as

will be seen from the diagram Fig. 8. The contacts m are secured to and in contact with the sleeve of brass i and the parts filled up with vulcanite to complete the circular periphery of the drum, as shown in Fig. 7. On the spindle e of the drum is a disk 3, to which is secured one end of a coiled spring 4, the

other endbeing secured to a fixed part of the switch, so that as the drum is rotated by the ratchet-and-pawl mechanism the spring is wound up.

The operator at the exchange is provided with a suitable operators switch A, Fig. 5, whereby a powerful battery B can be cut in to line, such switch having an indicator to show the number of impulses that have been given to the switch-magnets, and thereby indicating the number of the subscriber on the line who is in talking-circuit. The line apparatus may be described as follows: All subscribers are arranged in parallel, as shown in Fig. 5, on a metallic return for preference. In parallel working I provide a suitable high-inductance relay O of the necessary resistance across the loop or branchv from the main-line wiresin other words,

in shunt across the lineand arranged at each subscribers instrument or other suitable position on the loop branch or line, as the case may be. This relay is compound wound for reasons that will be apparent hereinafter. On this relay O being closed by the current sent through it by the operator at the exchange (hereinafter called the switching-current) a second path is open for the passage of the current-win, throughthe switch-magnet D, which is also in shunt across the line. This switch-magnet, being of comparatively low resistance and inductance,-is normally out out of the lineby the relay C of high inductance when the relay is ITO open-t. a, during the time that conversation is proceeding on the line afterthe necessary impulses have been sent over it; The fine-wire coil C in itself would be insuflicient 5 to maintain the closed. contact made by the armature of the relay. It is therefore necessary-to assist it by means of the coil D. "The fine-wire coil C of the relay is=for1the purpose of attracting the armature of the relay, thus ic'closing another circuitof. low resistance by -means of which the'limpulsecurrents amay inflow "through the electromagnet a,i'operating ithGSWlllClfU-dl'llll'l f. i This low-resistance circuit :will shortacircuit the higher resistance of: r3 the fine coil C. This would tend to weaken: *the -magnet-core of C-and D if 'the coil D were not included in the: low-resistance icir-' cu1t. rIt--will therefore be S66Il1'ltl'l5lt during .the time that conversation is :being carried 2o on the talking-current has-a clear path to line, i was "the high=resistance relays C are in= shunta acrosszthe line andtherefore can be neglected,

mowing to etheir high inductance. This in-= Pi ductance =may =bei increased by choking- 2 5- coils?i'n'series-With the relays C, if necessary, Min order rthatzthe comparativelyaslow alternationsofwthe :mag-neto bell currentszmay be= ;=-properly dealt with. :These choking-coils should; ibe of. the lowest possible resistance o compatible with their constructionior highrest impedance, that whey may not 'waste the rdirect current used tmoperat'e 'the switchem agnets and relays.

: 'lhe switchritself is 1 providedwith suitable 3 5 magnets for the purpose hereinafter=.de-

ascribed. First,=-magnets a, are iprovided, as

" already stated, to operate :the' switch-drum fl =by:ratchet-and-pawl mechanism by means of it/116 switching=currentg secondly,- in seriesor in o wparallel with these'magnets Iprovide as fur-- Ether magnet n; which is of suitable construction,cand when the xero -position is again ureached by" the 1 operators 'switchafter. ithe i termination of acallthe-switch is so arranged 5: that a reversal of the direction of the switchuing=current is obtained, and as the-second magnet n is ofzthe po larized type thisreven sisal. i of switching-current I every itime -:zero is "e-zspring .or other uneans. To efi ect this, the

6orarmature ocarries a :pin' 1)", Fig.1 2 1 disposed I :below pivotedvlever g, which is :thus lifted F by the: armature; the: lever graising the-pawl '1 brand locking-d etent 2 out: of engagement a withithe rat'chet-wheel Bythismeans all p 6 switches are broughtback to zero position simultaneously, and it will be seen, therefore, that-shouldany one of the-switches have missed an impulse, and thereby be out of synchronism with its-fellow switches, the reversal of the direction of the switching-current on zero position of operators switch will bring all-switches back into their correct po :sition iirreadiness for the next call, and thereby restore the lost synchronism which may have takenplace.

The telephone instruments are completely isolated' from the powerfulswitching-current by connecting up? through the 'medium of condensers- Eg' the condensers being no obstacle --to the bell and speaking currents, but 4 being an insurmountable-b arrier to the continuous currentdrom "the switching-battery.

' XIn theE arrangement shown in the drawings zero breaks all rlnglng and talking circuits,

"the zero brush 7"being normallyraised by a spring-actuated plunger 8 clear of Zero contact'Zon theldrum', as shownirrFig. 1, the other brushes v w being 'always in contact with the drum.

When .the'brush r is lowered intocontact ':with zero on :the drum by y a :s'ubscrib er ringing: and speaking cantake-place with the exchange operator-withoutcausing any of the otherbells in the circuit to' be rung. f =-To effect this, the-subscriber l presses a push-button; :causing' the. zero'brush to fall onto the -+-switch+drum by means of a'suit'able magnet t,

fitted in the switch=box, operated by the current from the transmitter-"battery; or auxiliary cellsrmay-be provided for this-purpose. The armature 'w is secured to the end of :the plunger 3 andis lowered by the electromagnet t against the'action of the spring 9c. "The instrument is thus cuti Linto dine, i thesub s'crib er rieleasingsaid push-buttoni after obt'aining i number required lcircuit then being through rthezbrushes v w, third or zero brush 1" bein'garaised. Should; however, theline be already engaged,:theswitch-drum is so arranged that a subscriber calling under these circumstanceslwill not be able to'cut iny-as it ..will be apparent on an inspection of Fig. 8

that zthewzero' contact l will have beenrremoved from below the zero brush.

' The contacts 7c m are so arranged: on the *switch-drums that on rotation- Esimultaneously by ithe switching-current suitable connections are made that subscribersspeak on outside lines or? are placed in intercommunication with "-each other Without I a Imultiplieity offbrushes' or compound circuits. For instance; and'referring to'Fig; 5, suppose No.

4- should' be asking exchange'for a number 'outside the party+line f'lhe-operatonwill give four impulses; as explained, whichwill rotate all the drums'in theseries -fourinter- "mittent movements corresponding in distance to the dotted lines shownuin- Fi 8.

- Zero contacts will then be all removed rom beneath zero brushes 1", so that no other subrrc ITS

- ator scriber can cut in. Brushes v w are then on contacts is m, (marked 4 on No. 4 drum,) all the other drums being cut out by the insulating material; No. 4 can then communicate with outside subscriber. Onthe other hand, should No. 4 ask for No. 1, the opergrives eight impulses, which, as will be seen om the diagram, Fig. 8, connects 1 to 4. In Fig. 5, 1 to 4 are shown connected, and it will be understood that in this 'figure parts of the apparatussuch as the receiver, bells, and the likeare not shown with respect to subscribers 2,3, and 5 for lack of space. Six impulses connect 1 and 2, ten impulses connect 2 and 3, and so on, a maXi mum number of fifteen impulses connecting 4 and 5. It will be understood that the number of subscribers may be varied, five having been instanced as a convenient number.

If desired, the zero brush 1" may always be in contact with the drum f, although this has the disadvantage of causing all bells to ring in the circuit. In such case it would not be necessary to provide means for raising and lowering the zero brush r.

The switching performed is an absolute cut-out and not a short-circuiting of the telephones not required.

Switch-magnets may be of the usual form,

or more powerful effects may be obtained by using permanent magnets of the magnetodynamo type, as shown in the drawings, the armature being suitably wound and of drum or ring or multipolar type, so as to be in balhandle A ance against the pull of the permanent magnets when no switching-current is passing, the reversal of current causing a reversal of movement of the armature on zero position, as required and hereinbefore described.

A stop 1 is provided to resist any tendency of the armatureo to rotate in the direc-' tion of the dotted arrow.

The operators switching apparatus consists of a vulcanite cylinder A, mounted on a spindle A which is rotated by the'crank- Projecting from the periphery of the said cylinder A are a number of teeth A and A of the form shown in the drawings. All of the said teeth with the exception of A 9 are situated on one side of the periphery, A being placed at the other side of the periphery, as will be seen from the plan view Fig. 10.

marked 1 and theteeth marked 4 andv 5. This latter space is just twice as wide as the space between the remainder of the teeth on The spacesbetween the teeth A are allequal except the space between that tooth,

with those marked A The other lever A is placed so that the tooth on its under side may engage the tooth A on the cylinder. If the cylinder is rotated in the direction of the arrow, the lever A will be raised as each tooth A passes underit'. The lever A will only be operated once in each revolution of the cylinderthat is, when the tooth A passes under it. Both levers A and A are of metal and are normally supported at one end by resting ona bar A but when the levers are raised they come in contact with another bar A The bars A and A are respectively coupled to the positive and negative terminals of a re easing the drum f, as described, so that the spring 4 will return it to Zero. The arrange-- ment is such that both levers cannot be raised at the same time, one always remaining in contact with A The principle of this reversing-switch is well known in telegra hy. The only novel part is the means by w l iich one lever A is arranged to lift many times in succession before the lever A is raised. The remaining portion of Fig. 10 shows the usual operators indicating, receiving, and transmitting apparatus, the plug P being used to put an outside subscriber onto the party-line.

. I declare that what I claim is 1. In a party-line telephone system, the

sisting of an electromagnet or the like, an ar mature influenced by such electromagnet, a drum having contacts thereon, a ratchetwheel secured to such drum, apawl actuated by the armature to rotate the ratchet-wheel and drum by impulses through the electromagnet, a spring coiled by the rotation of the drum, a brush for zero position, a spring-actuated plunger for normally holding the brush for zero position out of contact with the zero contact on the .drum, an armature on the plunger and an electromagnet to attract the armature and bring the brush on the zero contact, brushes for speaking contacts on the drum, and a magnet of the polarized type, the pawl and a locking-detent from the ratchet-wheel on a reversal of current being sen-t through the polarized magnet the springs returning all the drums in the party-line system to Zero, substantially as described.

2. In combination in a switch for partyline telephones, the switch drum or barrel consisting of a central steel or other metallic spindle, an insulating-bush on such spindle, a sleeve of conducting material on such bush, a

. switch-box for subscribers instruments, conv -c0nbinu0us=e0i1tact 7c Withproj'eetion for-Zero- -eontact,==and een-tacts m secured to ether, *sleeve, and ace-Impound brush 1" w and brush 1) substantiallyas' described.

7 3. Aswitch drum or-barrel'censisting of a central :steel or other meta-llimspindle; an in- 4 sulatin'g-bush h-on suehlspindle asleeve L of eonducjuingmaterialon such insulatingbush,

-:- a continuous contact lo 'with projection for zero-contact, and contacts mseeured to the' :sleeve.i substantially as: described.

4. Ina-party-line :belephene system in: each subscribersset; the combination ofa shunte eircuit ineluding the fine-Wire coil of a com- -:-p0u-ndvvound relay with a -parallelcircuit in-- -'-AL'FRED YATES. 

